> why are we trusting them with doing their jobs under such conditions?
Process, process, process. Or "train as you'll fight" in more bellicose terms. Drill and rote is the only way to get fallible humans to do the correct thing regardless of environment and conditions.
However it's when things occur for which there's no process in place that you need flexible, quick-thinking NCOs and officers. And that's achieved by constantly putting them into those scenarios, as the British Army learned in its 'small conflicts' since WW2. Analyse, assess, plan and react within minutes.
Unfortunately the higher echelons seldom retain that capability after years in stuffy corridors. It would be interesting to study the proportion of UFO "affirmations" originating from sharp-end military personnel versus desk-jockeys. I reckon the latter will be the vast majority.